linux-2.5.32_timer-change_A2

RFC PATCH New john stultz 1 participant 1 message Aug 29, 2002

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john stultz

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2002-08-29 02:14 UTC #0 lore raw

RFC PATCH 1/1 linux-2.5.32_timer-change_A2

Hi all,
Here is my timer-change patch resynced with 2.5.32. As I said before,
this patch breaks up arch/i386/kernel/time.c into various timer_pit, timer_tsc chunks. The hope is to cleanup the existing code so it doesn't care what type of clock is providing the high-resolution offset for gettimeofday. This will also simplify adding support for my cyclone-timer patch as well as ACPI pm timer or any other high res counter.

Right now I've just taken the existing code put all TSC releated code into one file, all PIT related code into another, and created struct timer_ops that provides a generic interface. I've avoided making any changes to the actual code, so its as transparent a change as possible.

My next rev will probably move __udelay into the timer_ops struct as well.

It compiles and boots on a few boxes here without problems, but I'd really like further testing and review. I'd also really appreciate any comments at all on this patch.

Might this be considered as a -dj candidate?

Flames and comments always welcome.

thanks
-john

arch/i386/kernel/Makefile +2 -2

diff -Nru a/arch/i386/kernel/Makefile b/arch/i386/kernel/Makefile
@@ -6,12 +6,12 @@
 
 O_TARGET := kernel.o
 
-export-objs     := mca.o msr.o i386_ksyms.o time.o
+export-objs     := mca.o msr.o i386_ksyms.o time.o timer_pit.o
 
 obj-y	:= process.o semaphore.o signal.o entry.o traps.o irq.o vm86.o \
 		ptrace.o i8259.o ioport.o ldt.o setup.o time.o sys_i386.o \
 		pci-dma.o i386_ksyms.o i387.o bluesmoke.o dmi_scan.o \
-		bootflag.o
+		bootflag.o timer.o timer_pit.o timer_tsc.o
 
 obj-y				+= cpu/
 obj-$(CONFIG_MCA)		+= mca.o

arch/i386/kernel/time.c +8 ~~-337~~

404 lines not on this page · raw message

arch/i386/kernel/timer.c new file +28 -0

diff -Nru a/arch/i386/kernel/timer.c b/arch/i386/kernel/timer.c
@@ -0,0 +1,28 @@
+#include <linux/kernel.h>
+#include <asm/timer.h>
+
+/*list of externed timers*/
+extern struct timer_opts timer_pit;
+extern struct timer_opts timer_tsc;
+
+/*list of timers, ordered by preference*/
+struct timer_opts* timers[] = {
+	&timer_tsc,
+	&timer_pit
+};
+
+#define NR_TIMERS (sizeof(timers)/sizeof(timers[0]))
+
+/* iterates through the list of timers, returning the first 
+ * one that initializes successfully.
+ */
+struct timer_opts* select_timer(void)
+{
+	int i;
+	/*find most preferred working timer*/
+	for(i=0; i < NR_TIMERS; i++)
+		if(timers[i]->init())
+			return timers[i];
+	panic("select_timer: Cannot find a suitable timer\n");
+	return 0;
+}

arch/i386/kernel/timer_pit.c new file +185 -0

185 lines not on this page · raw message

arch/i386/kernel/timer_tsc.c new file +215 -0

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include/asm-i386/timer.h new file +13 -0

diff -Nru a/include/asm-i386/timer.h b/include/asm-i386/timer.h
@@ -0,0 +1,13 @@
+
+#ifndef _ASMi386_TIMER_H
+#define _ASMi386_TIMER_H
+
+struct timer_opts{
+	int (*init)(void);
+	void (*mark_offset)(void);
+	unsigned long (*get_offset)(void);
+};
+
+#define TICK_SIZE tick
+struct timer_opts* select_timer(void);
+#endif